JPH10193745A - Image forming system and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the number of interface signal lines between an image control section and an engine control section by processing a preceding sheet feed command through serial communication. SOLUTION: When the forward end of a sheet arrives at a specified position, a microcomputer signals arrival of the sheet at the vertical image writing position to an image control section through serial communication and transmits a pixel data in synchronism with a horizontal sync signal. At an engine control section, a laser beam modulated by the pixel data is emitted from a semiconductor laser 18 in order to scan on a photosensitive drum 38 charged through a primary charger 39 thus forming a latent image on the surface thereof. The latent image is developed through a developer 36 into a toner image which is then transferred, by means of a transfer charger 40, onto a sheet being carried. The sheet is passed through a fixing unit comprising a heating roller 28 and a pressure roller 43 in order to fix the toner image and then discharged to a sheet discharge port designated by a print command.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus comprising, for example, an image control unit for generating an image signal, and an image forming unit for receiving the image signal from the image control unit and forming an image. It relates to a control method.

[0002]

2. Description of the Related Art A conventional image forming apparatus is disclosed in
As described in US Pat. No. 27743, JP-A-5-286608, etc., a paper feed port and a paper discharge port are designated in advance by serial communication from the image control unit, and the designated supply / discharge is designated by the engine control unit. It is configured to instruct the paper exit to start a paper feeding operation or a printing operation using a preceding paper feeding signal or a printing start signal.

[0003]

However, in the above-described conventional image forming apparatus, the video controller instructs the image forming apparatus to issue a print start command or a preceding paper feed command using a signal line provided for that purpose. Since the paper exit change command and the paper exit change command are issued using serial communication separate from the signal line, there are the following problems.

[0004] 1. An extra signal line was required for a print start command and a preceding paper feed command.

[0005] 2. When it is necessary to specify the paper supply / discharge port for each page, such as when performing double-sided printing, the supply / discharge port change command must be sent before the print start command or the preceding paper feed command. Instead, there were many communication processes.

SUMMARY OF THE INVENTION The present invention has been made in view of the above conventional example, and has as its object to provide an image forming apparatus in which the number of interface signal lines is reduced and communication processing is reduced, and a control method thereof.

[0007]

In order to achieve the above object, the present invention has the following arrangement. That is, an image forming means for forming an image on a recording medium passing through one of a plurality of paths based on the generated pixel data, and a predetermined operation involving movement of the recording medium on which the image is recorded by the image forming means Instruction information for instructing the image forming means to execute the predetermined operation by adding information of a path corresponding to a recording medium to be used to the instruction information for instructing the image forming means, wherein the image forming means comprises: The predetermined operation is executed so that the recording medium passes through any of the plurality of paths, based on the information on the path specified by (1).

Alternatively, based on a command from the image control unit via a serial communication line, an image is formed on a recording medium supplied from a specified supply port, and the recording medium is discharged to a specified discharge port. In the image forming apparatus, a step of determining that the command is a predetermined command; determining a discharge port of the recording medium included in the predetermined command; and discharging the determined discharge port of the recording medium according to the command. The method includes a step of setting a supply port of a recording medium included in the instruction and a step of setting the determined supply port as a supply port of a recording medium according to the instruction.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIGS. 1 and 2 show the features of a laser beam printer according to a first embodiment of the present invention.

FIG. 1 is a block diagram of the control unit of the laser beam printer. In FIG. 1, the printer is roughly divided into an image control unit 1 and an engine control unit 2. The image control unit 1 converts the coded image data from an external host computer or the like into bit-mapped pixel data, and sends the pixel data to the engine control unit 2.

The engine control unit 2 forms a toner image on the front or back surface of paper as a recording medium according to the pixel data received from the image control unit 1.

FIG. 2 is a sectional view showing the structure of the laser beam printer. Referring to FIG.
Is detachably mounted on the printer 100.

The operation of the printer according to the present embodiment will be described below with reference to FIGS. In FIGS. 1 and 2, common components are denoted by the same reference numerals.

In FIG. 1, the image control unit 1 has a CPU 7 as control means, and the CPU 7 has an external I / O
3, each of a pixel data RAM 4, a program ROM 5, a code storage RAM 6, a DMA controller 8, an engine control I / O 9, and a display unit 52 are connected via the internal bus 11. The internal bus 11 includes a data bus, an address bus, and a control bus, and each device can be accessed from the CPU 7.

The image control unit 1 as described above receives coded image data via an external interface 10 (for example, a Centronics type parallel interface or an RS-232 type serial interface). The code data is input to the external I / O3.

The CPU 7 converts the code data input via the external I / O 3 into R as an image data transmission preparation process.
AM6, and converts the code data into pixel data according to a predetermined format.
It is stored at a specific address of M4. This RAM 4 is a so-called bit map memory. A program for converting code data into pixel data is stored in the ROM 5. The conversion and the storage are performed in this manner, and the CPU 7 confirms that the engine control unit 2 described later can receive data, and activates the DMA controller 8.
Then, the DMA controller 8 occupies the internal bus 11 and reads pixel data stored in the RAM 4 from a predetermined address. When the DMA controller 8 becomes active, the CPU 7 and the DMA controller 8 alternately occupy the internal bus 11. DMA controller 8 is RAM
The pixel data is read from the predetermined address No. 4 and the data is converted into serial data. Then, an image signal 13 in which pixel data is serialized is transmitted to the engine control unit 2 in synchronization with a horizontal synchronization signal 14 received from the engine control unit 2 described later. The engine controller 2 forms a toner image according to the image signal 13.

As described above, the image control unit 1 converts the image data received from the outside into a serialized (ie, rasterized) image signal, and sends the signal to the engine control unit 2. In addition, the image control unit 1 has a role of instructing the engine control unit 2 to perform a specific operation via a serial communication line 12 as described later. A command for the operation is issued by an engine control I / O 9 to a one-chip microcomputer 15 as an image forming unit and a supply / discharge control unit.
Sent to That is, the one-chip microcomputer 15
Controls each unit of the engine control unit 2 and each unit of the double-sided conveyance unit 101 according to a command from the image control unit 1. Further, the image control unit 1 can know the internal information of the engine control unit 2 via the serial communication line 12.

Table 1 shows that the image control unit 1 uses the serial communication line 1
2 shows a format of a print command transmitted to the engine control unit 2 via the control unit 2.

[0019]

[Table 1]

The print command is a 16-bit command.
The first to eighth bits are fixed values, indicating that they are print commands. The ninth to twelfth bits specify the paper feed port using a 4-bit code, and the image control unit 1 specifies the paper feed port to be used in accordance with the codes in Table 2.

[0021]

[Table 2]

As described above, the ninth print command format is used.
The twelfth bit allows the user to specify the sheet feeding port to be any one of the tray 50, the cassette 33, and the duplex conveying unit 101.

The twelfth to fifteenth bits specify the discharge port with a 3-bit code.
Specify the paper output port to be used according to the code of

[0024]

[Table 3]

As described above, the first of the print command formats is
By the 3rd to 15th bits, the discharge port can be specified to be either face-down (FD) discharge or the duplex conveying unit 101.

The 16th bit is an odd parity bit which is 1
Bits are set so that the result of adding each of the 16 bits becomes an odd number.

When the image controller 1 issues a print command to the engine controller 2 via the serial communication line 12, the one-chip microcomputer 15 of the engine controller 2
And controls the engine unit according to the flowchart of FIG. First, in step S301, it is determined whether the received command (command) is a print command. If the command is a print command, the process proceeds to step S302. If it is not a print command, a command operation (not shown) corresponding to the command is performed. Step S3
In 02, it is determined whether or not the specification code of the discharge port indicated by the 13th, 14th, and 15th bits of the print command specifies double-sided discharge.
If not, the process proceeds to step S303.

In step S303, it is determined whether or not the specification code of the paper discharge port specifies face-down (FD) paper discharge. If the FD paper discharge is specified, the process proceeds to step S308.
If not, the process proceeds to step S304. In step S304, the execution of the print command is stopped without entering the printing operation because the designation code of the paper discharge port is invalid, and the image control unit 1 is notified of the fact.

In step S305, it is determined whether the next sheet can be fed into the duplex conveying unit 101. If the next sheet can be fed, the process proceeds to step S306. If the next sheet cannot be fed, the process proceeds to step S307. In step S306, the lever 46 is moved to set the discharge port to the duplex unit 101.
Set to. In step S307, since the double-sided paper cannot be discharged, the printing operation is stopped without executing the printing operation, and the image control unit 1 is notified of this.

In step S308, the lever 46 is moved to set the discharge port face down. Step S
At 309, it is determined whether or not the sheet feeding port designation code indicated by the ninth, tenth, eleventh, and twelfth bits of the print command designates tray feeding.
3 and if tray feed is not designated, step S310
Move to

In step S310, it is determined whether or not the specification code of the paper feeding port specifies cassette paper feeding. If the cassette paper feeding is specified, the process proceeds to step S316. If not, the process proceeds to step S311. Step S3
At 11, it is determined whether or not the sheet feeding port designation code designates a duplex unit. If the duplex unit is designated, the process proceeds to step S319, and if not, the process proceeds to step S312. In step S312, the execution of the print command is stopped without entering the print operation because the specification code of the paper feed port is incorrect, and the image control unit 1 is notified of the fact.

In step S313, it is determined whether or not paper is set on the tray 50.
The process proceeds to step S14, and if there is paper, the process proceeds to step S315. In step S314, since there is no paper in the designated tray 50, the printing operation is not started and the execution of the printing command is stopped, and the fact is notified to the image control unit 1. In step S315, when each part necessary for a printing operation described later is in a printable state, the paper feed roller 34 is driven to feed paper from the tray 50, and the flow advances to step S322.

In step S316, it is determined whether or not paper is set in the cassette 33. If there is no paper, the flow proceeds to step S317, and if there is paper, the flow proceeds to step S318.
In step S317, since there is no paper in the designated cassette 33, the printing operation does not start and the execution of the print command is stopped, and the image control unit 1 is notified of the fact. In step S318, when each part necessary for a printing operation described later is in a printable state, the paper feed roller 51 is driven, and the process proceeds to step S322 in which paper is fed from the cassette 33. Step S3
In step 19, it is determined whether a sheet is set in the duplex sheet re-feeding unit 101. If there is no sheet, the process proceeds to step S320. If there is a sheet, the process proceeds to step S321. Step S3
At 20, the designated double-sided sheet re-feeding unit has no paper, so that the printing operation is not started and the execution of the printing command is stopped, and the image control unit 1 is notified of this. In step S321, when each part necessary for a printing operation to be described later is in a printable state, the paper feed roller 49 is driven to feed paper from the duplex conveying unit 101, and the flow advances to step S322. Step S
At 322, the printing operation described below is performed.

When the engine control unit 2 receives the print command and enters the printing operation, it activates the laser scanner motor driver 21 and rotates the laser scanner motor 22. At the same time, the microcomputer 15 activates the main motor driver 23 and rotates the main motor 24 to rotate the photosensitive drum 38, the heating roller 28 and the pressure roller 43.
To rotate.

When the microcomputer 15 detects that the number of revolutions of the laser scanner motor 22 reaches a predetermined value, the laser control circuit 16 causes the semiconductor laser 18 to emit light. The emitted laser beam is scanned on the reflecting mirror 37 by the rotating polygon mirror 44. The laser beam reflected by the reflection mirror 37 scans on the photosensitive drum 38. On the other hand, the scanning position of the laser beam is detected by the light receiving element 20 arranged on the beam scanning, formed into a pulse signal by the beam detection circuit 19, and transmitted to the image control unit 1 as the horizontal synchronization signal 14 via the laser control circuit 16. Can be

After the microcomputer 15 starts rotating the main motor 24, the microcomputer 15 sequentially applies a high voltage to the primary charger 39, the developing device 36, and the transfer charger 40 via the high voltage generating circuit 45. Further, the heater driver 27 is controlled so that the temperature of the heating roller 28 becomes a predetermined temperature.

When each section reaches a printable state, the microcomputer 15 feeds the paper from the paper feed port designated by the print command, and monitors the transport state of the paper with the various sensors 26. When the leading edge of the paper reaches a predetermined position, the microcomputer 15 sends the image control unit 1 via the serial communication line 12.
Is transmitted to the image writing position in the vertical direction. The CPU 7 receives this information, activates the DMA controller 8, and sends out the pixel data in synchronization with the horizontal synchronization signal 14.

In the engine control unit 2, the laser driver 1 is controlled based on the pixel data transmitted via the image signal 13.
7, the semiconductor laser 18 generates a laser beam modulated with pixel data.

The generated laser beam is supplied to the primary charger 39.
Is scanned on the charged photosensitive drum 38 to form a latent image on the drum surface. The latent image is developed into a toner image by the developing device 36, and the toner image is transferred to the paper conveyed by the transfer charger 40. The paper to which the toner image has been transferred passes through a fixing device including a heating roller 28 and a pressure roller 43 to fix the toner image, and is then discharged to a paper discharge port designated by a print command.

As described above, by processing print commands using serial communication, the number of interface signal lines between the image control unit 1 and the engine control unit 2 can be reduced. Further, the number of serial communications can be reduced by simultaneously performing the print command and the paper supply / discharge port designation.

In the present embodiment, a laser beam printer is used as the engine unit, but other systems can be applied. (Second Embodiment) In the printer having the same configuration as that of the first embodiment, a description will be given of a preceding paper feed command for feeding paper to a predetermined position in advance.

Table 4 shows that the image control unit 1 uses the serial communication line 12
3 shows a format of a preceding paper feed command transmitted to the engine control unit 2 via the.

[0043]

[Table 4]

The preceding paper feed command is a 16-bit command, and the first to eighth bits are fixed values indicating that this command is a preceding paper feed command. The 9th to 12th bits specify the paper feed port with a 4-bit code.
The image control unit 1 specifies a paper feed port to be used according to the codes in Table 2. The twelfth to fifteenth bits specify the discharge port with a 3-bit code, and the image control unit 1 specifies the discharge port to be used according to the codes in Table 3. The 16th bit is an odd parity bit, which is set so that the result of adding each bit of 1 to 16 bits becomes an odd number.

When the image control unit 1 issues a preceding paper feed command to the engine control unit 2 via the serial communication line 12, the one-chip microcomputer 15 of the engine control unit 2 executes the procedure shown in the flowcharts of FIGS. Controls the engine.

First, in step S401, it is determined whether or not the received command (command) is a preceding paper feed command. If the command is a preceding paper feed command, the process proceeds to step S402. If it is not a preceding paper feed command, an operation (not shown) corresponding to the command is performed.

In step S402, the first sheet feed command
It is determined whether the discharge port designation code indicated by the 3rd, 14th, and 15th bits specifies double-sided discharge. If double-sided discharge is specified, the process proceeds to step S405; otherwise, the process proceeds to step S403. Move on.

In step S403, it is determined whether or not the specification code of the paper discharge port specifies face-down (FD) paper discharge. If the FD paper discharge is specified, the process proceeds to step S408.
If not, the process proceeds to step S404. In step S404, the execution of the preceding sheet feeding command is stopped without entering the preceding sheet feeding operation because the specification code of the sheet discharge port is incorrect, and the image control unit 1 is notified of the execution.

In step S405, it is determined whether the next sheet can be fed into the duplex conveying unit 101. If the next sheet can be fed, the process proceeds to step S406. If the next sheet cannot be fed, the process proceeds to step S407. In step S406, the lever 46 is moved to set the paper discharge ports on both sides. In step S407, since the double-sided paper cannot be discharged, the execution of the preceding paper feeding command is stopped without entering the preceding paper feeding operation, and the image control unit 1 is notified of the fact. In step S408, the lever 46 is moved to set the discharge port face down.

In step S409, it is determined whether or not the designation code of the sheet feeding port indicated by the ninth, tenth, eleventh, and twelfth bits of the preceding sheet feeding command designates tray sheet feeding. The process moves to S413, and if tray feed is not specified, the process moves to step S410.

In step S410, it is determined whether or not the specification code of the paper feeding port specifies cassette paper feeding. If the cassette paper feeding is specified, the process proceeds to step S416, and if not, the process proceeds to step S411.

In step S411, it is determined whether or not the specification code of the paper feeding port specifies double-sided paper feeding. If double-sided paper feeding is specified, the process proceeds to step S419. If not, the process proceeds to step S412. In step S412, the execution of the preceding sheet feeding command is stopped without entering the preceding sheet feeding operation because the designation code of the sheet feeding port is incorrect, and the image control unit 1 is notified of the execution.

In step S413, it is determined whether paper is set in the tray 50.
The process proceeds to step S414, and if there is a sheet, the process proceeds to step S415. In step S414, since there is no paper in the designated tray 50, the execution of the preceding sheet feeding command is stopped without entering the preceding sheet feeding operation, and the image control unit 1 is notified of that fact. Step S41
In FIG. 5, a feed roller 34 is provided for a preceding feed operation to be described later.
Is driven to feed paper from the tray 50 (step S4).
Move to 22.

In step S416, it is determined whether or not paper is set in the cassette 33. If there is no paper, the flow proceeds to step S417, and if there is paper, the flow proceeds to step S418.
In step S417, since there is no paper in the designated cassette 33, the execution of the preceding paper feeding command is stopped without entering the preceding paper feeding operation, and the image control unit 1 is notified of the execution. Step S4
In FIG. 18, the feed roller 5
1 is driven to feed paper from the cassette 33, and the flow advances to step S422.

In step S419, the duplex unit 10
It is determined whether a sheet is set in No. 1 and if there is no sheet, the process proceeds to step S420. If there is a sheet, the process proceeds to step S421. In step S420, since there is no paper in the designated duplex unit 101, the execution of the preceding paper feed command is stopped without entering the preceding paper feeding operation, and the image control unit 1 is notified of this.
In step S421, for the preceding sheet feeding operation described later,
The paper feed roller 49 is driven to feed paper from the duplex conveying unit 101, and the flow advances to step S422. Step S42
In 2, the preceding sheet feeding operation described below is performed.

When the engine control unit 2 receives the preceding paper feed command and enters the preceding paper feed operation, the paper fed from the paper feed port designated by the preceding paper feed designation is monitored by various sensors, and When the leading end reaches the registration roller 35, the driving of the registration roller 35 is stopped, and the paper conveyance is temporarily stopped. After this,
The microcomputer 15 continues this state until receiving the print command described in the first embodiment from the image control unit 1. However, when the supply / discharge port is specified by the preceding paper supply command, the paper supply port code is set to 0000b and the discharge port code is set to 000b. Microcomputer 15
When the feed code of the print command is 0000b and the discharge port code is 000b, the operation is performed so as to use the currently specified supply / discharge port.

As described above, the number of interface signal lines between the image control unit 1 and the engine control unit 2 can be reduced by processing the preceding paper feed command using serial communication. Further, the number of serial communications can be reduced by simultaneously performing the preceding sheet feeding instruction and the supply / discharge port designation.

[0058]

[Other Embodiments] Even if the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine) Machine, facsimile machine, etc.).

Another object of the present invention is to connect an attachable / detachable storage device for supplying a storage medium storing a program code of software for realizing the functions of the above-described embodiment to an image forming apparatus, Is supplied to the device, and the computer (first, second
In the embodiment, the present invention can also be achieved by a one-chip microcomputer 15) reading and executing a program code stored in a storage medium.

In this case, the program code itself read from the storage medium realizes the function of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) Performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, The case where the CPU of the function expansion board or the function expansion unit performs part or all of the actual processing, and the function of the above-described embodiment is realized by the processing.

[0064]

As described above, according to the present invention, the number of interface signal lines can be reduced, and
The number of times of serial communication can be reduced.

[0065]

[Brief description of the drawings]

FIG. 1 is a control system block diagram of an image forming apparatus.

FIG. 2 is a schematic configuration diagram of an image forming apparatus.

FIG. 3 is a control flowchart of an engine control unit according to the first embodiment.

FIG. 4 is a control flowchart of an engine control unit according to the first embodiment.

FIG. 5 is a control flowchart of an engine control unit according to the second embodiment.

FIG. 6 is a control flowchart of an engine control unit according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image control part 2 Engine control part 3 External I / O 4 RAM for image data 5 Program ROM 6 Code storage RAM 7 CPU 8 DMA controller 9 Engine control I / O 12 Serial signal line 15 1-chip microcomputer 16 Laser control circuit

Claims (7)

[Claims] An image forming unit configured to form an image on a recording medium passing through one of a plurality of paths based on the generated pixel data; and moving the recording medium on which the image is recorded by the image forming unit. Instruction information for instructing the accompanying predetermined operation, information of a path corresponding to a recording medium to be used is added, and instruction means for instructing the image forming means to execute the predetermined operation is provided, wherein the image forming means comprises: The image forming apparatus according to claim 1, wherein the predetermined operation is performed based on information on the path indicated by the instruction unit so that the recording medium passes through one of the plurality of paths. 2. The image forming unit according to claim 2, wherein the instruction unit adds, to the instruction information, information specifying one of a plurality of recording medium supply ports as a path through which the recording medium passes. 2. The image forming apparatus according to claim 1, wherein the recording medium is supplied from a designated paper supply port. 3. The image forming unit according to claim 2, wherein the instruction unit adds information specifying one of a plurality of recording medium outlets to the instruction information as a path through which the recording medium passes. 3. The image forming apparatus according to claim 1, wherein the recording medium is discharged from a designated discharge port. 4. The instruction means according to claim 1, wherein:
4. The image forming apparatus according to claim 1, wherein an instruction to start image formation is issued, and the image forming unit starts image formation based on the instruction information. 5. The instructing means includes:
4. An instruction to convey a recording medium to a position near a recording position prior to image formation, wherein the image forming unit conveys the recording medium to a predetermined position based on the instruction information. The image forming apparatus according to any one of the above. 6. An image is formed on a recording medium supplied from a specified supply port based on a command from the image control unit via a serial communication line, and the recording medium is discharged to a specified discharge port. In the image forming apparatus, a step of determining that the command is a predetermined command; and determining a discharge port of a recording medium included in the predetermined command,
Setting the determined outlet as the outlet of the recording medium according to the instruction; and determining the supply port of the recording medium included in the instruction, and setting the determined supply port to the supply port of the recording medium according to the instruction. Setting the image forming apparatus as a control method. 7. The image according to claim 6, wherein the predetermined command includes a print command for forming an image on a recording medium and a preceding paper feeding command for conveying the recording medium to a predetermined position. A method for controlling a forming apparatus.